1. Technical Field of the Invention
This disclosure relates in general to devices and methods that are used in burn-in systems, and more particularly, to an apparatus and method that provides for linked, slot-level burn-in of components.
2. Description of the Related Art
The term “burn-in” refers to an electrical stress test that employs voltage and temperature to accelerate the electrical failure of a device. Burn-in essentially simulates the operating life of the device, since the electrical excitation applied during burn-in may mirror the worst-case bias that the device will be subjected to in the course of its useable life. Depending on the burn-in duration used, the reliability information obtained may pertain to the device's early life or its wear-out. Burn-in may be used as a reliability monitor or as a production screen to weed out potential infant mortalities from the lot.
Burn-in is typically done at an elevated temperature while electrical excitation is applied to the sample devices. The burn-in process is facilitated by using burn-in boards (BIBs). A number of sample devices may be placed on each BIB, and the BIBs are then inserted into a burn-in chamber that supplies the necessary voltages to the samples while maintaining the chamber at the desired temperature. The burn-in chamber includes a number of chamber slots, each slot configured to accommodate one BIB and the components that it holds. The electrical bias applied to the devices may either be static or dynamic, depending on the failure mechanism that is being accelerated during the burn-in process.
Some conventional component burn-in systems are not automated. That is, operators must manually load the BIBs with devices, place the BIBs in the slots of the burn-in chamber, remove the BIBs, remove the baked devices from the BIBs, and then repeat the process for the other unbaked devices.
Other conventional burn-in systems are partially automated. For example, a conventional piece of automated equipment that is often used in burn-in systems is known as a Burn-in board Loader/Unloader (BLU). The BLU may be used to mechanically load devices from a JEDEC tray to a BIB or vice versa. The term “JEDEC tray” refers to a component packaging tray that is standardized across the industry for each type of device package, i.e., Pin Grid Array packages (PGAs), Ball Grid Array packages (BGAs), Ceramic Quad Fine Pitch packages (CQFPs), etc. However, once the components are transferred to the BIBs, the operators must still manually transfer the BIBs to the other units of the burn-in system, for example, the burn-in chamber. Since the BLUs and burn-in chambers of a conventional burn-in system are typically spread widely throughout a room, trolleys or carts are used to manually transport a large number of trays or BIBs to, from, or between the BLUs and burn-in chambers.
The conventional systems and methods of burn-in described above are manually intensive, costly, and require large physical spaces. Conventional burn-in systems are also susceptible to “staging”, meaning that because the system components are not linked, the operators will typically wait until a trolley or cart is completely filled with BIBs before moving the BIBs to the burn-in chamber. Embodiments of the invention address these and other disadvantages inherent in the above-described conventional burn-in systems.